Though the Italian often does not celebrate his goals, and can cut a moody figure on the bench, Milner believes there has been nothing unprofessional about Balotelli's attitude.
"I don't think anyone is happy when they are not in the team," said Milner. "But he hasn't shown it. He trains hard every day.
"He goes about his business like everyone else does. You try to get in the side and when you get a chance, try to take it.
"He has not stepped out of line or shown his disappointment in any way."
He added: "He is a top-quality player. You forget how young he is and he has done a lot in the game already. You can see his quality every time he comes on.
"He only needed half a chance (against Everton) and he took it. It wasn't an easy finish. He is a massive part of this squad as well. He is a goalscorer."